NASA’s Kepler Discovers First Earth-Size Planet in Habitable Zone

Today NASA announced the discovery of the first Earth-size exoplanet orbiting in a “habitable zone.”

The planet, named Kepler-186f, was discovered by the Kepler Space Telescope, and while it isn’t the first planet we’ve seen in a habitable zone, it is the first Earth-size planet of its kind that we’ve found.

“Kepler-186f resides in the Kepler-186 system, about 500 light-years from Earth in the constellation Cygnus. The system is also home to four companion planets, which orbit a star half the size and mass of our sun. The star is classified as an M dwarf, or red dwarf, a class of stars that makes up 70 percent of the stars in the Milky Way galaxy.”

Lisa Quintana, a research scientist at the SETI Institute at NASA’s Ames Research Center, was the lead author of the paper published today outlining the discovery.

“We know of just one planet where life exists – Earth,” she says, “When we search for life outside our solar system we focus on finding planets with characteristics that mimic that of Earth. Finding a habitable zone planet comparable to Earth in size is a major step forward.”

However, it’s unclear at this time if the planet is actually habitable.

It’s in a “habitable zone,” but its mass and temperature are still undetermined. Because of this, co-author Thomas Barclay likens Kepler-186f to an “Earth-cousin.”

“It has many properties that resemble Earth,” he says.

Further investigation will need to be done with satellites able to determine the composition of these planets. So don’t pack your bags just yet.

Still, it seems like only a matter of time before we find true “Earth twins” orbiting sun-like stars.